//---------------------------------------------------------------------
//  This file is part of the Background Motion solution.
// 
//  Copyright (C) Mindscape (TM).  All rights reserved.
//  http://www.mindscape.co.nz
// 
//  THIS CODE AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
//  PARTICULAR PURPOSE.
//---------------------------------------------------------------------

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;

namespace Mindscape.BackgroundMotion.Core.Utilities
{
  /// <summary>
  /// Represents a set container
  /// </summary>
  /// <typeparam name="TItem"></typeparam>
  [SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
  public class Set<TItem> : ICollection<TItem>
  {
    private readonly Dictionary<TItem, object> _dictionary
      = new Dictionary<TItem, object>();

    /// <summary>
    /// Adds an item to the <see cref="T:System.Collections.Generic.ICollection`1"></see>.
    /// </summary>
    /// <param name="item">The object to add to the <see cref="T:System.Collections.Generic.ICollection`1"></see>.</param>
    /// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"></see> is read-only.</exception>
    public void Add(TItem item)
    {
      _dictionary[item] = true;
    }

    /// <summary>
    /// Removes all items from the <see cref="T:System.Collections.Generic.ICollection`1"></see>.
    /// </summary>
    /// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"></see> is read-only. </exception>
    public void Clear()
    {
      _dictionary.Clear();
    }

    /// <summary>
    /// Determines whether the <see cref="T:System.Collections.Generic.ICollection`1"></see> contains a specific value.
    /// </summary>
    /// <param name="item">The object to locate in the <see cref="T:System.Collections.Generic.ICollection`1"></see>.</param>
    /// <returns>
    /// true if item is found in the <see cref="T:System.Collections.Generic.ICollection`1"></see>; otherwise, false.
    /// </returns>
    public bool Contains(TItem item)
    {
      return _dictionary.ContainsKey(item);
    }

    /// <summary>
    /// Copies the elements of the <see cref="T:System.Collections.Generic.ICollection`1"></see> to an <see cref="T:System.Array"></see>, starting at a particular <see cref="T:System.Array"></see> index.
    /// </summary>
    /// <param name="array">The one-dimensional <see cref="T:System.Array"></see> that is the destination of the elements copied from <see cref="T:System.Collections.Generic.ICollection`1"></see>. The <see cref="T:System.Array"></see> must have zero-based indexing.</param>
    /// <param name="arrayIndex">The zero-based index in array at which copying begins.</param>
    /// <exception cref="T:System.ArgumentOutOfRangeException">arrayIndex is less than 0.</exception>
    /// <exception cref="T:System.ArgumentNullException">array is null.</exception>
    /// <exception cref="T:System.ArgumentException">array is multidimensional.-or-arrayIndex is equal to or greater than the length of array.-or-The number of elements in the source <see cref="T:System.Collections.Generic.ICollection`1"></see> is greater than the available space from arrayIndex to the end of the destination array.-or-Type T cannot be cast automatically to the type of the destination array.</exception>
    public void CopyTo(TItem[] array, int arrayIndex)
    {
      throw new NotImplementedException();
    }

    /// <summary>
    /// Gets the number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"></see>.
    /// </summary>
    /// <value></value>
    /// <returns>The number of elements contained in the <see cref="T:System.Collections.Generic.ICollection`1"></see>.</returns>
    public int Count
    {
      get { return _dictionary.Count; }
    }

    /// <summary>
    /// Gets a value indicating whether the <see cref="T:System.Collections.Generic.ICollection`1"></see> is read-only.
    /// </summary>
    /// <value></value>
    /// <returns>true if the <see cref="T:System.Collections.Generic.ICollection`1"></see> is read-only; otherwise, false.</returns>
    public bool IsReadOnly
    {
      get { return false; }
    }

    /// <summary>
    /// Removes the first occurrence of a specific object from the <see cref="T:System.Collections.Generic.ICollection`1"></see>.
    /// </summary>
    /// <param name="item">The object to remove from the <see cref="T:System.Collections.Generic.ICollection`1"></see>.</param>
    /// <returns>
    /// true if item was successfully removed from the <see cref="T:System.Collections.Generic.ICollection`1"></see>; otherwise, false. This method also returns false if item is not found in the original <see cref="T:System.Collections.Generic.ICollection`1"></see>.
    /// </returns>
    /// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1"></see> is read-only.</exception>
    public bool Remove(TItem item)
    {
      return _dictionary.Remove(item);
    }

    /// <summary>
    /// Returns an enumerator that iterates through the collection.
    /// </summary>
    /// <returns>
    /// A <see cref="T:System.Collections.Generic.IEnumerator`1"></see> that can be used to iterate through the collection.
    /// </returns>
    public IEnumerator<TItem> GetEnumerator()
    {
      return _dictionary.Keys.GetEnumerator();
    }

    /// <summary>
    /// Returns an enumerator that iterates through a collection.
    /// </summary>
    /// <returns>
    /// An <see cref="T:System.Collections.IEnumerator"></see> object that can be used to iterate through the collection.
    /// </returns>
    IEnumerator IEnumerable.GetEnumerator()
    {
      return GetEnumerator();
    }
  }
}